In Lee's To Kill a Mockingbird, what is the difference between Calpurnia's and Lula's views on white people?

In chapter 12 of Lee's To Kill a Mockingbird, Calpurnia takes Jem and Scout to her church because Atticus is out of town on business. Most of the people in the African American congregation accept the two white children as their guests with genuine hospitality, but Lula does not. As Calpurnia guides Scout and Jem up the path towards the church, she hears Lula's voice from behind her: "What you up to, Miss Cal?" Scout recalls that Calpurnia is nervous at this moment because her hands seem to dig into the little girl's shoulders. Lula confronts Calpurnia by saying the following:

"I wants to know why you bringin' white chillun to nigger church" (119).

Calpurnia explains with confidence that the children are her "comp'ny," which should set Lula at rest, but it doesn't. Usually, when someone has guests, or company, the rules of hospitality should take precedence over any petty concerns. However, Lula is not satisfied with Calpurnia's response, and she interrogates Cal further as follows:

"You ain't got no business bringin' white chillun here--they got their church, we got our'n. It is our church, ain't it, Miss Cal?" (119).

Calpurnia responds by saying that both races worship the same God, which implies that race shouldn't matter when it comes to attending church. Lula eventually backs down, but the children feel unwelcome and want to go home. Calpurnia won't let Lula's prejudices against whites affect her decision to take the children to church, though. From the conversation between the two women, it is evident that Lula is prejudiced and Cal is not. That doesn't mean that Calpurnia is pro-white or against her own kind. 

Consequently, Calpurnia demonstrates that both races should be able to coexist, especially when it comes to attending church. Just because the white population of Maycomb won't allow black people to enter their churches, this doesn't mean that Cal has to return evil for evil in her life. Lula, on the other hand, believes that if she isn't allowed in a white person's church because of the color of her skin, then she should not have to allow white people into hers. Again, Calpurnia believes that since they all worship the same God, the color of one's skin shouldn't matter where they worship.